1. Field of the Invention
The present invention relates to a watch case, and more particularly to a structure of a watch case using a cemented carbide alloy.
2. Prior Art
The watch cases using cemented carbide alloy have an attractive ground surface and a high hardness. Those watch cases are hard enough to retain their original attractive appearance without scratches. Such watch cases have come into widespread use in recent years. However, the cemented carbide alloy is hard and brittle and, when it is machined, the machining methods which can be used are limited to machining, grinding, polishing and the like. The cemented carbide alloy therefore, can be applied only to the very simple-shape cases.
When a bezel is made using the cemented carbide alloy, it is not possible to form a structure in which the bezel is fixed by a packing, or a structure in which the upper portion of the packing is concealed by a flange composed of the cemented carbide alloy. If a C-shaped packing accommodating groove is formed in an unitary case band composed of the cemented carbide alloy, grinding or discharge machining must be employed. Such machining operations present major difficulties in view of cost, machining precision and design restrictions.
Further, conventional watch cases which employ cemented carbide alloy have considerable thickness because of the difficulty of machining the cemented carbide alloy. Accordingly, it is difficult to produce a thin, compact and attractive watch case.
The present invention seeks to overcome the above-mentioned problems encountered in the prior art.